How to encourage self-seeding?

[kGarden]

I would like the areas where I am naturalising some Snowdrops (near / under some deciduous trees) to extend by themselves, with some help from me.

I'd appreciate tips on encouraging them to self seed, and any suggestions you have for species / varieties to plant to encourage some cross-fertilization perhaps such that there might be some variation in the naturalised plants over the coming decades.

One of my issues is with the weeds that grow in these areas during Summer, and a lack of time to hand weed them (with other commitments elsewhere in the garden), so I would like to adopt chemical warfare on the weeds! Timing is obviously important, and in another thread someone suggested that late spraying with Roundup / Glyphosate could mean that there was still chemical that the emerging plants could come into contact with. I could mulch heavily with, say, Bark chips, but I suspect that is counter productive to getting self seedlings going.  Having said that I put a good 4" layer of well rotted / composted manure on my shrubbery a year or two back, completely covering a clump of Alliums, and the following Spring I had a forest of seedlings - never had a single one before - so maybe they can push through quite some depth?

[Sean Fox]

I thought that one of the benefits about using glyphosate was that it was "deactivated" on contact with soil.
 Another angle would be to add natural woodland plants to this "weedy" area to make it more appealing to the eye.The weeds may actually be beneficial in keeping the area relatively dry during the dormant season. You could then hack it all back at the end of the season ready for spring.

[Michael J Campbell]

I have a raised bed planted with Snowdrops, Crocus and Anemone  which gets sprayed with glyphosate every summer with no ill effects. The Anemone are seeding all over the bed.

See pic below,it looks ok.

[kGarden]

I thought that one of the benefits about using glyphosate was that it was "deactivated" on contact with soil.

Yes, that was my expectation too, until the comment was raised in another thread.

You could then hack it all back at the end of the season ready for spring.

Hadn't thought of that. The stuff that seems to grow there is low & green during the winter, and thus gets in the way of enjoying the Snowdrops, but I could try to encourage something more herbaceous that died down properly during the winter.

[RichardW]

I have a raised bed planted with Snowdrops, Crocus and Anemone  which gets sprayed with glyphosate every summer with no ill effects. The Anemone are seeding all over the bed.

See pic below,it looks ok.

ditto, my apple bank gets sprayed with agri strength throughout the summer with no sign of harm to the drops, the singles I planted as a trial patch 5+ years ago continue to spread vigorously.

[Carolyn Walker]

I garden and run my nursery completely organically and without weeds.  I recommend that you grind up your leaves in the fall and use the ground leaves thickly as mulch in your snowdrop area to keep the weeds down.  I do this over my naturalized snowdrops under deciduous trees and they thrive---I have thousands if not more.  The snowdrops themselves are almost weedy and plant themselves in many locations where I don't actually want them.  Here is a post from my blog about how to do this simply with your lawnmower: http://carolynsshadegardens.com/2012/10/25/your-most-precious-garden-resource/.  Please message or email me if you have any questions.

Carolyn

[Gene Mirro]

I've found that self-seeding occurs best in soil with a loose or crumbly surface.  I get a lot of self-seeding under a one-inch mulch of wood chips, and in sandy loam soil.  I get poor self-seeding in heavy clay loam soil.  You should also control slugs.

I have killed bulbs with Roundup applied in Winter.  I suspect that the soil bacteria aren't very active, so the Roundup gets to the roots of the bulbs.  Even in warm weather, I would spot-spray the Roundup in small quantities if bulbs are present.

kGarden, I would not recommend letting the weeds grow.  Never let weeds go to seed in the garden.  And some weeds will make perennial rootstocks that are nearly impossible to get rid of.  I recommend mulching with bark or gravel.  You will still have to do some weeding.  But do it when the weeds are small.